On the possible increasing of efficiency of ship power plant with the system combined of marine diesel engine, gas turbine and steam turbine in case of main engine cooperation with the gas turbine fed in parallel and the steam turbine

The article presents a concept of a combined large-power ship propulsion system, composed of the leading internal combustion main engine associated with a power gas turbine and the steam turbine system, both utilising the energy taken from the main engine exhaust gas. In the examined variant the power turbine, arranged in parallel with a turbocharger, is fed with the exhaust gas from the exhaust manifold. A calculation algorithm is presented, along with sample calculations for particular subsystems: supercharging, gas power turbine, and steam turbine system. Assumptions were formulated for the calculations, and were complemented by the adopted limits. Selected system parameters were confronted with the experimental investigations available in the literature. The performed power optimisation of the entire combined marine power plant took only into account the thermodynamic point of view, leaving aside technical and economic aspects. The numerical calculations were performed for the 52 MW low-speed marine diesel engine.